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SU Lyn is a purely accretion-powered symbiotic star revealed for us from X-rays. Its weak high-exciting emission lines rendered it invisible to optical surveys. While indicating that the already significant total estimated Galactic population of symbiotics openParvirgul3x10elev5closePar is biased and thus underestimated comma this discovery opens a new window on accretion and evolution of symbiotics. Here we propose XMM-Newton observations of two targets to go deeper in the subjectdoublePoint openPariclosePar SU Lyn comma to better understand the response of the accretion disk and boundary layer to changes in accretion rate comma and openPariiclosePar IGR J17164-3803 comma in an exploratory effort to validate it as a member of the class.

SU Lyn是一颗仅以吸积供能的共生星（symbiotic star），通过X射线（X-rays）观测首次被发现。其微弱的高激发发射线（emission lines）使其无法被光学巡天（optical surveys）所探测。该发现不仅表明，此前学界估算的银河系共生星总数量约为3×10^5存在偏差，实际数量被低估，同时还为共生星的吸积过程与演化研究打开了全新的窗口。在此我们提议使用XMM-牛顿望远镜（XMM-Newton）对两个目标开展观测：其一为SU Lyn，以更深入地开展相关研究，从而更好地理解吸积盘（accretion disk）与边界层（boundary layer）对吸积率（accretion rate）变化的响应；其二为IGR J17164-3803，通过探索性研究验证其是否属于共生星类别。